The device described is designed for mosquito control. Modern approaches to mosquito control include uses of chemicals (insecticides) to kill both adult and immature stages of mosquitoes. Chemicals are also used to repel mosquitoes (topical repellents) as they approach humans to bite e.g., OFF, etc.
Traps designed to capture adult mosquitoes (adult mosquito traps) have recently become popular with homeowners. This popularity is a result of growing problems of mosquitoes and mosquito-borne diseases in urban areas. These traps are specifically designed to attract adult female mosquitoes as they search for a warm-blooded host to bite.
Environmentalists have worked to stop uses of insecticides for mosquito control. In particular, environmentalist pressures have eliminated all modern options for use of the long-acting chemicals that in earlier years were used to reduce or eliminate many of the insect-borne diseases. Beyond the severe limitations imposed by environmentalist pressures, the chemicals themselves are only as effective as they are effectively used. Effective use is dependent on frequency of use, method of application, timing of applications, and characteristics of mosquitoes that are being targeted for control. In the hands of experts, the chemicals can be highly effective. In the hands of the typical homeowner, the use of chemicals is commonly ineffective and wasteful.
Topical repellents can protect an individual from mosquito bites. However, repellents are expensive, require frequent application to the skin, and are often unpleasant to the user. Based on their claims that the repellents harm or potentially harm children, special interest groups are working to stop use of topical repellents. Some people are actually allergic to the repellent chemicals. In spite of these problems, repellents are useful for individual protection against mosquito bites.
Adult mosquito traps are designed to attract the generic female mosquito. The problem with traps for control of mosquitoes relate to a trap's inability to competitively attract each type of mosquito that might be biting in the backyard of the typical urban homeowner. There are only a few species of mosquitoes that are common in backyards and even fewer that tend to bite humans. Unfortunately, modern traps do not specifically attract and capture the more important mosquitoes. Additionally, traps are expensive to buy, expensive to maintain, and commonly characterized by homeowners as ineffective.
A major problem of mosquitoes in backyards relates to the numbers of human-biting mosquitoes that are present. In some cases, traps might capture large numbers of mosquitoes but have little influence on numbers biting humans. Indeed, great numbers of mosquitoes might be collected in traps without successfully reducing the numbers biting humans and laying eggs for the next generation. As a consequence large numbers of mosquitoes might be produced in the local environment to continually replenish numbers captured in traps. Moreover, the trap may not competitively capture mosquitoes that move into a backyard in response to the attractant emitted by a trap. Under such circumstances, the trap might actually increase the number of mosquitoes in the homeowner's backyard and result in more bites.
Trap brochures typically declare that use of adult mosquito traps should be only one of several approaches to mosquito control. Often the manufacturer recommends that homeowners also practice habitat reduction, also referred to as “source reduction,” to control mosquitoes. Mosquitoes are produced in large and small bodies of water in and around houses. Source reduction methods are almost always directed at reducing (emptying/draining) the bodies of standing water in backyards and adjoining sites. The goal of source reduction is to reduce chances that mosquitoes will have water for laying eggs and producing the next generation of biting mosquitoes.
Until now, an alternative to source reduction has not been technologically feasible. One alternative approach is to attract mosquitoes to an optimal site for laying eggs, allow the mosquito to lay her eggs, then harvest and destroy the immature stages after the eggs hatch. The technology for an alternative or supplement to source reduction is the subject of the present invention.
Mosquitoes require water for eggs to hatch and for the immature stages to undergo growth and development. Each different mosquito species will make use of its own preferred type of water. Growth stages of mosquitoes are aquatic and are called “larvae” (plural) or “larva” (singular).
Source reduction by homeowners consists of emptying water from all containers in yards as well as routinely cleaning gutters and surface drainage to eliminate bodies of standing water. Source reduction has been promoted as a means of mosquito control for decades. Source reduction has also been proposed as an approach to disease control. Decades of efforts have shown that this approach to mosquito control is dependent on a high level of user compliance (the homeowner must exert great and continuous effort). Basically, source reduction has proven to be highly ineffective.
The device described below addresses the need for an alternative or supplement to source reduction. The device incorporates new technologies for selectively capturing the mosquito's progeny and a mechanism for destroying the progeny without the use of chemicals. Additionally, the device can be equipped with mosquito species-specific attractants. Using species-specific attractants, the device can be highly effective against mosquitoes that pose the greatest threats to humans. Described is an enabling technology that can be used in traps to continuously trap mosquito larvae produced in birdbaths, can be used in traps for tree hole breeding mosquitoes, can be used to trap species responsible for the West Nile Virus transmission to birds and/or humans, can be used to trap and destroy the Asian Tiger mosquito that poses great problems in backyards in many urban areas, or can be used in floating traps designed for use in backyard garden ponds. Each trap will require specific design characteristics; but the underlying technology will be the same.
For perspective, much research has focused on defining specific attractants for egg-laying female mosquitoes. Although we can produce water that will stimulate gravid females of important species of mosquitoes to visit and lay eggs, we have no specific and efficient means of killing these mosquitoes once attracted to the water body. In particular, we have no means of continuous, low-maintenance capturing and killing of mosquitoes. Attempts have been made to attract mosquitoes to traps treated with toxic chemicals. However, toxic chemicals can result in an unhealthy body of water and the chemicals often repel or irritate mosquitoes and drive them away before the females lay eggs. Oviposition traps have been developed that prevent the females from exiting once they enter to lay eggs. Such traps have special entry portals that are, in one way or another, constricted to prevent exiting. Constricting entry portals also serve to discourage females from entering in the first place, so they function at low levels of efficiency. Another approach is to attract mosquitoes to water equipped with a vacuum device that will aspirate female mosquitoes. Thus, there is a need for continuous operation of the aspirator and its relatively high energy requirements are clear obstacles to routine use of this type of trap.
The water column technology is an enabling technology. For the first time, this technology enables use of research that has identified many new attractants for gravid mosquitoes. In this context, water treatments can be targeted to attract different species of mosquitoes. For example, decomposing hay material or small packets of rabbit food can be used to produce water that is highly attractive to the mosquitoes that are largely responsible for transmitting West Nile Virus to birds and to humans. Specific attractants have now been developed for attracting gravid females of Aedes aegypti mosquitoes. These mosquitoes are responsible for transmitting dengue viruses to humans in urban environments. Such attractants are, in some cases, species-specific. Thus, the attractants could be used in combination with water column technology to lure important species to the water, stimulate them to lay eggs, and then collect and destroy their progeny. This technology offers an alternative or supplement to source reduction which has proven ineffective in controlling mosquito and disease problems.
The functional elements of the device, take advantage of basic behaviors of mosquito larvae. Important aspects of mosquito larval behavior are as follows: 1) most mosquito larvae must come to the water surface to breath; 2) mosquito larvae are highly mobile within the confines of their water body and move or swim by switching the rear section of their long worm-shaped bodies back and forth; 3) when disturbed, larvae dive to the bottom of the water body; 4) most larvae actually dive to the bottom to feed; but must return to the surface to breathe; 5) larvae that encounter a sloped surface while swimming to the bottom will move down along the sloped surface to reach the bottom; and 6) larvae that encounter a sloped surface while moving to the surface will move upward along the sloped surface to reach the water surface.
Accordingly, it is desirable to provide a method and apparatus that harvests and disposes of these mosquito larvae. The device described below can operate on solar energy and battery power. The device requires energy; but its energy requirements are low and occur in short infrequent intervals.